Bis(arene)vanadium complexes. A structural study

Braga, Dario; Sabatino, Piera

doi:10.1107/s0108270190006539

Cited by 9 publications

(2 citation statements)

References 14 publications

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“…Within experimental error the average V−C distance of 1 , 2.21(4) Å, is identical with the average Cr−C distance of 2.17(2) Å found for Cr(C 10 H 8 ) 2 . Similar average V−C distances have also been reported for other bis(arene)vanadium(0) species, including V(mesitylene) 2 (2.20(1) Å), V(benzene) 2 (2.17 Å), and V(p-C 6 H 4 F 2 ) 2 (2.19(2) Å) . The average C−C distance of 1.39(4) Å is indistinguishable from corresponding values in Cr(C 10 H 8 ) 2 (1.41(3) Å) 22 and free naphthalene (1.41(2) Å) …”

Section: Resultssupporting

confidence: 83%

First Conventional Syntheses and Isolation of Bis(naphthalene)metal(0) Complexes. Structural Characterization of V(η⁶-C₁₀H₈)₂¹

et al. 1997

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Reactions of alkali-metal naphthalenides with VCl3(THF)3, CrCl3(THF)3, MoCl3(THF)3, and MoCl4(THF)2 in THF provided up to 29%, 24%, 20%, and 17% yields of the respective bis(naphthalene)metal(0) complexes. These highly reactive “naked” early-transition-metal atom reagents were accessible previously as pure substances only from metal atom reactions carried out in specialized apparatus available to few chemists. The nature of bis(naphthalene)vanadium(0) has been confirmed by a single-crystal X-ray structural characterization. These results provide another indication that the arene radical anion route is an important general strategy for the synthesis of homoleptic transition-metal arene complexes.

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Section: Resultssupporting

confidence: 83%

First Conventional Syntheses and Isolation of Bis(naphthalene)metal(0) Complexes. Structural Characterization of V(η⁶-C₁₀H₈)₂¹

et al. 1997

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“…(2), R = CN (3), R = CH 3 (4), R = CF 3 of the CH 3 group in (3) is shifted by 0.066 Å from the C 6 -ring plane away from the Cr atom. A similar structural feature was observed for other bis-arene complexes of transition metals containing -electron-donating substituents [CH 3 (Braga & Sabatino, 1990;Calderazzo et al, 1992), NMe 2 (Elschenbroich et al, 2003)] in the phenyl rings. Unexpectedly, unlike the previously studied neutral bisarene complexes containing -electron-withdrawing groups (Cl, COOH, CF 3 ) in aromatic ligands, in which these substituents are virtually coplanar with the phenyl rings, the CN groups in (2)-(4) are shifted towards Cr from the plane of the rings.…”

Section: Parameterssupporting

confidence: 78%

Substituent effects in bis(arene)chromium compounds containing a CN group in the aromatic ring

Khrustalev

Vasil’kov

Antipin

2005

Acta Crystallogr Sect B

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The crystal structures of Cr(PhCN)(2) (2), (PhCN)Cr(PhCH(3)) (3) and (PhCN)Cr(PhCF(3)) (4) prepared by means of the Metal Vapor Synthesis (MVS) technique have been determined. Compounds (2), (3) and (4) crystallize as discrete sandwich complexes having intrinsic C(2v)(mm2), C(s)(m) and C(1)(1) symmetries, respectively. The X-ray diffraction study has revealed a synperiplanar conformation for (2) and (3), and a synclinal conformation for (4) with a torsion angle (C(ipso)1-Centroid1-Centroid2-C(ipso)2) of phi = 63.5 degrees . The angles between the ligand planes are 2.2, 3.9 and 1.8 degrees , respectively. The Cr atom is slightly (by 0.04-0.06 A) displaced towards the substituents from the line connecting the centers of the opposite aromatic rings. The Cr-C(ipso) distances are 2.115 (2)-2.137 (2), 2.112 (2) and 2.185 (3) A for CN, CF(3) and CH(3) groups, respectively. The CN groups as well as the H atoms lie out of the C(6) ring planes and are bent towards the Cr atom, but the C atom of the CH(3) group also lying out of the C(6) ring plane is bent away from the Cr atom. The C atom of the CF(3) group is essentially coplanar to the C(6) ring plane. There are no unusual intermolecular contacts in the structures of (2)-(4).

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Synthesis and Reactivity of Mixed Arene Halides of Niobium(I). Crystal and Molecular Structure of Nbmes₂ and [Nbmes₂(CO)][Nb₂(μ‐I)₃(CO)₈]

et al. 1992

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Bis(mesitylen)niobium(O), Nbmes,, prepared via the NbC15/A1/ AlCl,/mes system by exaustive reduction in the presence of 1,2-dimethoxyethane or tetrahydrofuran as previously reported, has been studied by X-ray diffraction methods. The sandwich molecule has parallel, substantially planar, aromatic rings, in an eclipsed conformation. Nbmes, is oxidized to NbmeszX by reaction with l,lf-dimethy1-4,4'-bipyridinium halides [methylviologen halides, mvX, (X = C1, I)]. The reaction of both halo compounds with CO yielded the niobium (1) derivatives [Nbmes,(CO) Recently, we reported that the reaction of NbXs with Al/ AlX3 in mesitylene followed by low-temperature treatment of the reaction mixture with 1,2-dimethoxyethane and/or tetrahydrofuran afforded the bis-mesitylene derivative of niobium(O), Nbmes2. The reactivity of this compound has been investigated: the niobium(0) derivative is prone to oxidation to niobium(1) and can be easily reduced to niobium( -I), especially in the presence of carbon monoxide ['].In the framework of our studies concerning the low-valent derivatives of group 5 metals, we now report on the crystal and molecular structure of the parent compound, Nbmes,, the preparation of mixed halide-arene derivatives of niobium(1) and their reaction with CO affording the dinuclear anion [Nb2(p-I)j(CO)s] -as the [Nbmes2(CO)] + derivative. Results and DiscussionAfter several attempts, large red crystals of the paramagnetic [h8 (21°C) = 1.87 BM] Nbmes, were grown from pentane at -30°C, and the structure of the compound was solved. It consists of a sandwich molecule where the niobium atom is bound to two almost parallel (dihedral angle, 2.9 ") and planar (maximum deviation of the carbon atoms from the least-squares plane 0.007 A) mesitylene rings (Figure 1).The methyl substituents, which are in an eclipsed conformation (Figure 2) show only small deviations from the ring plane, the value of 0.104 A being the maximum deviation.The central niobium atom exhibits distances of 1.849(1) and 1.850(1) A from the ring planes, the Nb-C mean distance ranging from 2.305(5) to 2.362(5) 8. The mean C-C distances within the aromatic rings are 1.410(7) and 1.508(7) A. Several zerovalent bis(arene)metal complexes, mainly concerning chromium, have been structurally characterizedm. It is interesting to note that most of them show planar and parallel aromatic rings[2",b~d-nnl and adopt an eclipsed conformation both for benzene and alkylbenzene complexcribed[2d1 vanadium complex follow the same trend. Although in the niobium complex the interatomic repulsion is certainly lower than in 3d systems due to the larger size of the central metal atom, the eclipsed conformation in both the neutral and the cationic [Nbmes,(CO)] + complex (vide infra) is somewhat surprising. This problem, which is outside the scope of this paper, certainly deserves further attention.es P-e,h,ml. . the niobium derivative as well as a recently des-

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Bis(arene)vanadium complexes. A structural study

Cited by 9 publications

References 14 publications

First Conventional Syntheses and Isolation of Bis(naphthalene)metal(0) Complexes. Structural Characterization of V(η⁶-C₁₀H₈)₂¹

First Conventional Syntheses and Isolation of Bis(naphthalene)metal(0) Complexes. Structural Characterization of V(η⁶-C₁₀H₈)₂¹

Substituent effects in bis(arene)chromium compounds containing a CN group in the aromatic ring

Synthesis and Reactivity of Mixed Arene Halides of Niobium(I). Crystal and Molecular Structure of Nbmes₂ and [Nbmes₂(CO)][Nb₂(μ‐I)₃(CO)₈]

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Bis(arene)vanadium complexes. A structural study

Cited by 9 publications

References 14 publications

First Conventional Syntheses and Isolation of Bis(naphthalene)metal(0) Complexes. Structural Characterization of V(η6-C10H8)21

First Conventional Syntheses and Isolation of Bis(naphthalene)metal(0) Complexes. Structural Characterization of V(η6-C10H8)21

Substituent effects in bis(arene)chromium compounds containing a CN group in the aromatic ring

Synthesis and Reactivity of Mixed Arene Halides of Niobium(I). Crystal and Molecular Structure of Nbmes2 and [Nbmes2(CO)][Nb2(μ‐I)3(CO)8]

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First Conventional Syntheses and Isolation of Bis(naphthalene)metal(0) Complexes. Structural Characterization of V(η⁶-C₁₀H₈)₂¹

First Conventional Syntheses and Isolation of Bis(naphthalene)metal(0) Complexes. Structural Characterization of V(η⁶-C₁₀H₈)₂¹

Synthesis and Reactivity of Mixed Arene Halides of Niobium(I). Crystal and Molecular Structure of Nbmes₂ and [Nbmes₂(CO)][Nb₂(μ‐I)₃(CO)₈]